Remo monacoremo

monacoremo / totp.pg.sql

Created January 21, 2020 15:35 — forked from bwbroersma/totp.pg.sql

TOTP implementation for https://github.com/PostgREST/postgrest/issues/1250#issuecomment-551847083

	CREATE EXTENSION pgcrypto;
	CREATE OR REPLACE FUNCTION totp(key BYTEA, clock_offset INT DEFAULT 0) RETURNS INT AS $$
	DECLARE
	c BYTEA := '\x000000000' \|\| TO_HEX(FLOOR(EXTRACT(EPOCH FROM NOW()) / 30)::INT + clock_offset);
	mac BYTEA := HMAC(c, key, 'sha1');
	trunc_offset INT := GET_BYTE(mac, 19) % 16;
	result INT := SUBSTRING(SET_BIT(SUBSTRING(mac FROM 1 + trunc_offset FOR 4), 7, 0)::TEXT, 2)::BIT(32)::INT % 1000000;
	BEGIN
	RETURN result;
	END;